Processing Results from DADA2 to make plots, do some statistics

Link to notebook

Link to github repo.

Load packages

library(tidyverse)
library(readxl)
library(phyloseq)
library(dada2)
library(Biostrings)
library(DECIPHER)
library(phangorn)
library(readr)
library(seqinr)
library(decontam)
library(ape)
library(vegan)
#library(philr)
library(RColorBrewer)
library(microbiome)
library(DESeq2)
library(compositions);
library(cowplot)
library(plotly)
library(htmlwidgets)
library(withr)

Import and prepare the data from eDNA

Import Metadata

metadata <- read_csv("sample_data.csv")

── Column specification ────────────────────────────────────────────────────────────────────────────────────
cols(
  SampleID = col_character(),
  `Year.Trawl#` = col_character(),
  Datecode = col_double(),
  Date = col_character(),
  Month = col_double(),
  Year = col_double(),
  Bayside = col_character(),
  Station = col_character()
)

Import DADA2 results:

Import count table and taxonomy file. I slightly modified otutable.csv in Excel to otutable_mod.csv to remove the quotes around seq names and put NA placehoder as first col name (which was above row names)

# Import Count table. Skip first row of tsv file, which is just some text
count_table <- read_table2("results/otutable_mod.csv")

Missing column names filled in: 'X1' [1]
── Column specification ────────────────────────────────────────────────────────────────────────────────────
cols(
  .default = col_double(),
  X1 = col_character()
)
ℹ Use `spec()` for the full column specifications.

colnames(count_table)[1] <- "SampleID"

# Import taxonomy of ASVs
taxonomy <- read_csv(file="results/tax_sequences_blast_taxonomy.csv")

Missing column names filled in: 'X1' [1]Duplicated column names deduplicated: 'RefSeq_Tax_ID' => 'RefSeq_Tax_ID_1' [18]
── Column specification ────────────────────────────────────────────────────────────────────────────────────
cols(
  X1 = col_double(),
  ASV_ID = col_character(),
  ref_seq_ID = col_character(),
  PID = col_double(),
  alnmt_len = col_double(),
  mismatch = col_double(),
  eval = col_double(),
  bscore = col_double(),
  RefSeq_Tax_ID = col_double(),
  Ref_Seq_title = col_character(),
  superkingdom = col_character(),
  phylum = col_character(),
  class = col_character(),
  order = col_character(),
  family = col_character(),
  genus = col_character(),
  species = col_character(),
  RefSeq_Tax_ID_1 = col_double()
)

# remove first col of sequential numbers
taxonomy[,1] <- NULL
# filter out sequences with low PID (recommended by Sara)
taxonomy <- filter(taxonomy, PID > 92)

# remove BLAST metadata and just retain taxonomy (necessary for further processing below)
drop.cols <- c(colnames(taxonomy)[2:9],'RefSeq_Tax_ID_1')
taxonomy <-  select(taxonomy, -one_of(drop.cols))


# And import the Common names, as curated by Sara. Join to taxonomy
commonnames <- read_excel("Trawls MASTER 2020 _mod_ES.xlsx",7)
commonnames

taxonomy <- left_join(taxonomy, commonnames, by = "ASV_ID")
taxonomy

NA

Filtering removed seqs 110, 332 (Gobiosoma ginsburgi and Belone belone) Note for Sara should we consider setting this at 97% which is more robust and still leaves 334 unique ASVs (rather than 379 with the 92% cutoff in the settings above)

Preview datasets

count_table

taxonomy

metadata

Make phyloseq object

I want to use the phyloseq package for some plotting/ statistics, which first requires making phyloseq objects out of each of input data tables-

count_table_matrix <- as.matrix(count_table[,2:392]) # convert count table to matrix, leaving out character column of sample ID
rownames(count_table_matrix) <- count_table$SampleID # add back in Sample IDs as row names
ASV =   otu_table(count_table_matrix, taxa_are_rows =  FALSE)

taxonomy_matrix <- as.matrix(taxonomy[,2:9])
rownames(taxonomy_matrix) <- taxonomy$ASV_ID 
TAX =   tax_table(taxonomy_matrix)

META    =   sample_data(data.frame(metadata, row.names = metadata$`SampleID`))

First check that the inputs are in compatible formats by checking for ASV names with the phyloseq function, taxa_names

head(taxa_names(TAX))

[1] "Seq_1" "Seq_2" "Seq_3" "Seq_4" "Seq_5" "Seq_6"

head(taxa_names(ASV))

[1] "Seq_1" "Seq_2" "Seq_3" "Seq_4" "Seq_5" "Seq_6"

And check sample names were also detected

# Modify taxa names in ASV, which are formatted with the sample ID, underscor, fastq ID. Don't need this fastq ID anymore and want it to match the sample names from metadata
sample_names(ASV) <-  sample_names(ASV) %>%
  str_replace_all(pattern = "_S[:digit:]+",replacement = "")


head(sample_names(ASV))

[1] "T1PosCon" "T1S10"    "T1S11"    "T1S1"     "T1S2"     "T1S3"    

head(sample_names(META))

[1] "T1PosCon" "T1S1"     "T1S2"     "T1S3"     "T1S5"     "T1S6"    

And make the phyloseq object

ps <- phyloseq(ASV, TAX,    META)

Quality check and filtering- eDNA

Rarefaction curves

rarecurve(otu_table(ps), step=50, cex=0.5)

empty rows removed

# save as .eps
setEPS()
postscript("Figures/rarefaction.eps")

rarecurve(otu_table(ps), step=50, cex=0.5)

empty rows removed

dev.off()

quartz_off_screen 
                2 

Most samples look like they were sampled to completion. Be weary of T3S11, T1S2, and maybe T4S5

Filtering

Check some features of the phyloseq object

rank_names(ps)

[1] "superkingdom" "phylum"       "class"        "order"        "family"       "genus"        "species"     
[8] "CommonName"  

unique(tax_table(ps)[, "superkingdom"])

Taxonomy Table:     [2 taxa by 1 taxonomic ranks]:
        superkingdom
Seq_1   "Eukaryota" 
Seq_377 NA          

unique(tax_table(ps)[, "phylum"])

Taxonomy Table:     [3 taxa by 1 taxonomic ranks]:
        phylum      
Seq_1   "Chordata"  
Seq_368 "Arthropoda"
Seq_377 NA          

unique(tax_table(ps)[, "class"])

Taxonomy Table:     [5 taxa by 1 taxonomic ranks]:
        class           
Seq_1   "Actinopteri"   
Seq_63  "Mammalia"      
Seq_362 "Chondrichthyes"
Seq_368 "Insecta"       
Seq_377 NA              

There are some ASVs with NA as superkingdom, phylum, or class annotation- delete these.

ps <- subset_taxa(ps, !is.na(superkingdom) & !is.na(phylum) & !is.na(class))

unique(tax_table(ps)[, "superkingdom"])

Taxonomy Table:     [1 taxa by 1 taxonomic ranks]:
      superkingdom
Seq_1 "Eukaryota" 

unique(tax_table(ps)[, "phylum"])

Taxonomy Table:     [2 taxa by 1 taxonomic ranks]:
        phylum      
Seq_1   "Chordata"  
Seq_368 "Arthropoda"

unique(tax_table(ps)[, "class"])

Taxonomy Table:     [4 taxa by 1 taxonomic ranks]:
        class           
Seq_1   "Actinopteri"   
Seq_63  "Mammalia"      
Seq_362 "Chondrichthyes"
Seq_368 "Insecta"       

nrow(tax_table(ps)) # number of ASVs left

[1] 378

378 ASVs still remain…

Also check class Mammalia, to see if contamination or real:

tax_table(subset_taxa(ps, class == 'Mammalia'))

Taxonomy Table:     [8 taxa by 8 taxonomic ranks]:
        superkingdom phylum     class      order          family      genus   species        CommonName 
Seq_63  "Eukaryota"  "Chordata" "Mammalia" "Primates"     "Hominidae" "Homo"  "Homo sapiens" "Human"    
Seq_88  "Eukaryota"  "Chordata" "Mammalia" "Artiodactyla" "Suidae"    "Sus"   "Sus scrofa"   "Wild boar"
Seq_157 "Eukaryota"  "Chordata" "Mammalia" "Primates"     "Hominidae" "Homo"  "Homo sapiens" "Human"    
Seq_343 "Eukaryota"  "Chordata" "Mammalia" "Carnivora"    "Felidae"   "Felis" "Felis catus"  "Cat"      
Seq_369 "Eukaryota"  "Chordata" "Mammalia" "Artiodactyla" "Bovidae"   "Bos"   "Bos taurus"   "Cattle"   
Seq_378 "Eukaryota"  "Chordata" "Mammalia" "Primates"     "Hominidae" "Homo"  "Homo sapiens" "Human"    
Seq_383 "Eukaryota"  "Chordata" "Mammalia" "Primates"     "Hominidae" "Homo"  "Homo sapiens" "Human"    
Seq_389 "Eukaryota"  "Chordata" "Mammalia" "Primates"     "Hominidae" "Homo"  "Homo sapiens" "Human"    

These are human, wild boar, cat (…cat lady), and cattle. All are contamination so delete all Mammalia

ps <- subset_taxa(ps, !class == 'Mammalia')
unique(tax_table(ps)[, "class"])

Taxonomy Table:     [3 taxa by 1 taxonomic ranks]:
        class           
Seq_1   "Actinopteri"   
Seq_362 "Chondrichthyes"
Seq_368 "Insecta"       

Next check the “Insecta” entries

tax_table(subset_taxa(ps, class == 'Insecta'))

Taxonomy Table:     [2 taxa by 8 taxonomic ranks]:
        superkingdom phylum       class     order         family       genus         species             
Seq_368 "Eukaryota"  "Arthropoda" "Insecta" "Hymenoptera" "Formicidae" "Linepithema" "Linepithema humile"
Seq_380 "Eukaryota"  "Arthropoda" "Insecta" "Hymenoptera" "Formicidae" "Linepithema" "Linepithema humile"
        CommonName
Seq_368 "Ant"     
Seq_380 "Ant"     

The onlly Insecta is Linepithema humile, which are ants so delete these too..

ps <- subset_taxa(ps, !class == 'Insecta')
unique(tax_table(ps)[, "class"])

Taxonomy Table:     [2 taxa by 1 taxonomic ranks]:
        class           
Seq_1   "Actinopteri"   
Seq_362 "Chondrichthyes"

Plot total sequences by phyla to check out sequencing effort

Check overall how the phyla are distributed among samples

# First aglomerate the ASVs at the phylum level using the phyloseq function, tax_glom
superkingdomGlommed = tax_glom(ps, "superkingdom")

# and plot
plot_bar(superkingdomGlommed, x = "Sample")

ggsave(filename = "Figures/seqdepth.eps", plot = plot_bar(superkingdomGlommed, x = "Sample"), units = c("in"), width = 9, height = 6, dpi = 300, )# and save

Total sequences reveals certain samples had very low sequencing effort: T1S7, T1S8, T3S11, and, not as bad, T1S2 and T4S5

The rarefaction analysis also showed T1S2 and T4S5 samples were likely not sequenced to completion. Therefore remove these 5 samples from analysis

ps <- subset_samples(ps, !SampleID == "T1S7" & !SampleID == "T1S8" & !SampleID == "T3S11" & !SampleID == "T1S2" & !SampleID == "T4S5")

ps

phyloseq-class experiment-level object
otu_table()   OTU Table:         [ 368 taxa and 50 samples ]
sample_data() Sample Data:       [ 50 samples by 8 sample variables ]
tax_table()   Taxonomy Table:    [ 368 taxa by 8 taxonomic ranks ]

50 samples remaining with 368 ASVs

Remove Pos Controls (all hits in positive controls are the same family- I assume this is expected)

ps <- subset_samples(ps, !SampleID == "T1PosCon" & !SampleID == "T2PosCon" & !SampleID == "T3PosCon")
ps

phyloseq-class experiment-level object
otu_table()   OTU Table:         [ 368 taxa and 47 samples ]
sample_data() Sample Data:       [ 47 samples by 8 sample variables ]
tax_table()   Taxonomy Table:    [ 368 taxa by 8 taxonomic ranks ]

And lastly, correct some taxonomy: According to Sara, Engraulis encrasicolus (European anchovy) should be Anchoa mitchilli (Bay anchovy):

tax_table(ps) <- gsub(tax_table(ps), pattern = "Engraulis encrasicolus", replacement = "Anchoa mitchilli")  

47 samples remainwith 368 unique ASVs

Abundance plots- eDNA

For plotting, use relative abundances (# of ASV sequences/sum total sequences in sample), calculated easily using microbiome::transform

ps_ra <- microbiome::transform(ps, transform = "compositional")

Export the relative abundance matrix so Sara can have it:

# Extract abundance matrix from the phyloseq object
RelAbun_matrix = as(otu_table(ps_ra), "matrix")

# Coerce to data.frame
RelAbun_dataframe = as.data.frame(RelAbun_matrix)

# Export
write.csv(RelAbun_dataframe,"results/otutable_relabun.csv", row.names = TRUE)

Plot abundance of families from all samples to do some quality control

Then aglomerate the ASVs at the family level using the phyloseq function, tax_glom

familyGlommed_RA = tax_glom(ps_ra, "family")
family_barplot <- plot_bar(familyGlommed_RA, x = "Sample", fill = "family")
family_barplot

NOTES for Sara

• There are some samples, (T1S3, T1S6, T2S11, T3S10, T3S4, T3S5, T3S9, T4S4, T4S7, T5S7) which are composed almost exclusively of 1 family. This might be fine, but I’m not used to seeing this with prokaroytic data. Just want to check with you

Agglomerate by species to see if I get the same 38 unique species Sara sees:

speciesGlommed_RA = tax_glom(ps_ra, "CommonName")
speciesGlommed_RA

phyloseq-class experiment-level object
otu_table()   OTU Table:         [ 43 taxa and 47 samples ]
sample_data() Sample Data:       [ 47 samples by 8 sample variables ]
tax_table()   Taxonomy Table:    [ 43 taxa by 8 taxonomic ranks ]

tax_table(speciesGlommed_RA)

Taxonomy Table:     [43 taxa by 8 taxonomic ranks]:
        superkingdom phylum     class            order                family           
Seq_1   "Eukaryota"  "Chordata" "Actinopteri"    "Atheriniformes"     "Atherinopsidae" 
Seq_2   "Eukaryota"  "Chordata" "Actinopteri"    "Clupeiformes"       "Clupeidae"      
Seq_3   "Eukaryota"  "Chordata" "Actinopteri"    "Clupeiformes"       "Engraulidae"    
Seq_4   "Eukaryota"  "Chordata" "Actinopteri"    "Scombriformes"      "Pomatomidae"    
Seq_5   "Eukaryota"  "Chordata" "Actinopteri"    "Lutjaniformes"      "Lutjanidae"     
Seq_6   "Eukaryota"  "Chordata" "Actinopteri"    "Pleuronectiformes"  "Paralichthyidae"
Seq_7   "Eukaryota"  "Chordata" "Actinopteri"    "Clupeiformes"       "Clupeidae"      
Seq_9   "Eukaryota"  "Chordata" "Actinopteri"    "Gobiiformes"        "Gobiidae"       
Seq_10  "Eukaryota"  "Chordata" "Actinopteri"    "Pleuronectiformes"  "Scophthalmidae" 
Seq_11  "Eukaryota"  "Chordata" "Actinopteri"    "Perciformes"        "Serranidae"     
Seq_12  "Eukaryota"  "Chordata" "Actinopteri"    "Spariformes"        "Sparidae"       
Seq_15  "Eukaryota"  "Chordata" "Actinopteri"    NA                   "Sciaenidae"     
Seq_16  "Eukaryota"  "Chordata" "Actinopteri"    NA                   "Sciaenidae"     
Seq_17  "Eukaryota"  "Chordata" "Actinopteri"    "Labriformes"        "Labridae"       
Seq_19  "Eukaryota"  "Chordata" "Actinopteri"    "Perciformes"        "Cottidae"       
Seq_20  "Eukaryota"  "Chordata" "Actinopteri"    "Pleuronectiformes"  "Pleuronectidae" 
Seq_21  "Eukaryota"  "Chordata" "Actinopteri"    NA                   "Moronidae"      
Seq_22  "Eukaryota"  "Chordata" "Actinopteri"    "Syngnathiformes"    "Syngnathidae"   
Seq_30  "Eukaryota"  "Chordata" "Actinopteri"    "Pleuronectiformes"  "Paralichthyidae"
Seq_33  "Eukaryota"  "Chordata" "Actinopteri"    NA                   "Sciaenidae"     
Seq_34  "Eukaryota"  "Chordata" "Actinopteri"    "Labriformes"        "Labridae"       
Seq_36  "Eukaryota"  "Chordata" "Actinopteri"    "Anguilliformes"     "Anguillidae"    
Seq_38  "Eukaryota"  "Chordata" "Actinopteri"    "Scombriformes"      "Scombridae"     
Seq_40  "Eukaryota"  "Chordata" "Actinopteri"    "Perciformes"        "Gasterosteidae" 
Seq_44  "Eukaryota"  "Chordata" "Actinopteri"    "Cyprinodontiformes" "Fundulidae"     
Seq_50  "Eukaryota"  "Chordata" "Actinopteri"    "Atheriniformes"     "Atherinopsidae" 
Seq_52  "Eukaryota"  "Chordata" "Actinopteri"    "Gadiformes"         "Phycidae"       
Seq_54  "Eukaryota"  "Chordata" "Actinopteri"    "Scombriformes"      "Scombridae"     
Seq_57  "Eukaryota"  "Chordata" "Actinopteri"    "Perciformes"        "Triglidae"      
Seq_67  "Eukaryota"  "Chordata" "Actinopteri"    "Scombriformes"      "Scombridae"     
Seq_82  "Eukaryota"  "Chordata" "Actinopteri"    NA                   "Sciaenidae"     
Seq_84  "Eukaryota"  "Chordata" "Actinopteri"    "Gadiformes"         "Gadidae"        
Seq_102 "Eukaryota"  "Chordata" "Actinopteri"    "Clupeiformes"       "Engraulidae"    
Seq_103 "Eukaryota"  "Chordata" "Actinopteri"    "Perciformes"        "Cottidae"       
Seq_115 "Eukaryota"  "Chordata" "Actinopteri"    "Cyprinodontiformes" "Fundulidae"     
Seq_119 "Eukaryota"  "Chordata" "Actinopteri"    "Gadiformes"         "Phycidae"       
Seq_139 "Eukaryota"  "Chordata" "Actinopteri"    "Batrachoidiformes"  "Batrachoididae" 
Seq_141 "Eukaryota"  "Chordata" "Actinopteri"    "Scombriformes"      "Scombridae"     
Seq_181 "Eukaryota"  "Chordata" "Actinopteri"    "Tetraodontiformes"  "Tetraodontidae" 
Seq_231 "Eukaryota"  "Chordata" "Actinopteri"    "Gadiformes"         "Merlucciidae"   
Seq_359 "Eukaryota"  "Chordata" "Actinopteri"    "Perciformes"        "Triglidae"      
Seq_362 "Eukaryota"  "Chordata" "Chondrichthyes" "Myliobatiformes"    "Myliobatidae"   
Seq_372 "Eukaryota"  "Chordata" "Chondrichthyes" "Carcharhiniformes"  "Triakidae"      
        genus                species                         CommonName                
Seq_1   "Menidia"            "Menidia menidia"               "Atlantic silverside"     
Seq_2   "Brevoortia"         "Brevoortia tyrannus"           "Atlantic menhaden"       
Seq_3   "Engraulis"          "Anchoa mitchilli"              "Bay anchovy"             
Seq_4   "Pomatomus"          "Pomatomus saltatrix"           "Bluefish"                
Seq_5   "Lutjanus"           "Lutjanus griseus"              "Grey snapper"            
Seq_6   "Paralichthys"       "Paralichthys dentatus"         "Summer flounder"         
Seq_7   "Alosa"              "Alosa mediocris"               "Hickory shad"            
Seq_9   "Gobiosoma"          "Gobiosoma ginsburgi"           "Seaboard goby"           
Seq_10  "Scophthalmus"       "Scophthalmus aquosus"          "Windowpane flounder"     
Seq_11  "Centropristis"      "Centropristis striata"         "Black seabass"           
Seq_12  "Stenotomus"         "Stenotomus chrysops"           "Scup"                    
Seq_15  "Leiostomus"         "Leiostomus xanthurus"          "Spot"                    
Seq_16  "Menticirrhus"       "Menticirrhus saxatilis"        "Northern kingfish"       
Seq_17  "Tautoga"            "Tautoga onitis"                "Tautog"                  
Seq_19  "Myoxocephalus"      "Myoxocephalus aenaeus"         "Grubby sculpin"          
Seq_20  "Pseudopleuronectes" "Pseudopleuronectes americanus" "Winter flounder"         
Seq_21  "Morone"             "Morone saxatilis"              "Striped bass"            
Seq_22  "Syngnathus"         "Syngnathus fuscus"             "Northern pipefish"       
Seq_30  "Etropus"            "Etropus microstomus"           "Smallmouth flounder"     
Seq_33  "Cynoscion"          "Cynoscion regalis"             "Weakfish"                
Seq_34  "Tautogolabrus"      "Tautogolabrus adspersus"       "Cunner"                  
Seq_36  "Anguilla"           "Anguilla rostrata"             "American eel"            
Seq_38  "Thunnus"            "Thunnus obesus"                "Bigeye tuna"             
Seq_40  "Apeltes"            "Apeltes quadracus"             "Fourspine stickleback"   
Seq_44  "Fundulus"           "Fundulus majalis"              "Striped killifish"       
Seq_50  "Membras"            "Membras martinica"             "Rough silverside"        
Seq_52  "Urophycis"          "Urophycis floridana"           "Spotted hake"            
Seq_54  "Scomber"            "Scomber japonicus"             "Chub mackerel"           
Seq_57  "Prionotus"          "Prionotus carolinus"           "Northern searobin"       
Seq_67  "Thunnus"            "Thunnus thynnus"               "Atlantic bluefin tuna"   
Seq_82  "Bairdiella"         "Bairdiella chrysoura"          "American silver perch"   
Seq_84  "Microgadus"         "Microgadus tomcod"             "Atlantic tomcod"         
Seq_102 "Engraulis"          "Engraulis mordax"              "Bay anchovy"             
Seq_103 "Myoxocephalus"      "Myoxocephalus quadricornis"    "Fourhorn sculpin"        
Seq_115 "Fundulus"           "Fundulus heteroclitus"         "Mummichog"               
Seq_119 "Urophycis"          "Urophycis floridana"           "Red hake"                
Seq_139 "Opsanus"            "Opsanus tau"                   "Oyster toadfish"         
Seq_141 "Katsuwonus"         "Katsuwonus pelamis"            "Skipjack tuna"           
Seq_181 "Sphoeroides"        "Sphoeroides maculatus"         "Northern puffer"         
Seq_231 "Merluccius"         "Merluccius bilinearis"         "Silver hake"             
Seq_359 "Prionotus"          "Prionotus evolans"             "Striped searobin"        
Seq_362 "Rhinoptera"         "Rhinoptera bonasus"            "Cownose ray"             
Seq_372 "Mustelus"           "Mustelus canis"                "Dusky smooth-hound shark"

NOTES for Sara

• I am actually getting 43 unique species- which ones am I missing that should be removed?
• Also there are two species you are calling Bay anchovy- Engraulis mordax and Anchoa mitchilli. Should the Engraulis mordax be changed to Anchoa mitchilli, similar to Engraulis encrasicolus ?

Bubble plots

Based on my previous scripts with Cariaco Eukaryotic data

# convert ps object to dataframe using phyloseq's psmelt
species_df <- psmelt(speciesGlommed_RA)

# replace zeroes in the table with NA
species_df[species_df == 0] <- NA

# and remove rows with NAs in abundance  (this is so they don't appear as small dots in plot)
species_df <-  filter(species_df, !is.na(Abundance))

Plot by species, scientific name

bubbleplot_eDNA_sciname <- ggplot(species_df, aes(x = Station, y = fct_rev(species), color = Station)) + # the fancy stuff around y (species) helps to present it in reverse order in the plot (from top to btm alphabetically)
  geom_point(aes(size = Abundance, fill = Station), color = "black", pch = 21)+
  scale_size(range = c(1,15)) +
  scale_size_area(breaks = c(0,.25,.5,.75,1), max_size = 6)+
  xlab("")+
  ylab("")+
  labs(size="Relative Abundance")+
  theme_bw() +
  scale_fill_brewer(palette="Paired") +
  theme(axis.title.x=element_blank(),
        axis.text.x=element_blank(),
        axis.ticks.x=element_blank()) +
  facet_grid(Datecode~Bayside, scales = "free", space = "free", drop= TRUE)

Scale for 'size' is already present. Adding another scale for 'size', which will replace the existing
scale.

bubbleplot_eDNA_sciname

Plot by species common name

Exportfigures

ggsave(filename = "Figures/speciesbubbleplot_eDNA_sciname.eps", plot = speciesbubbleplot_eDNA_sciname, units = c("in"), width = 7, height = 12, dpi = 300)

ggsave(filename = "Figures/speciesbubbleplot_eDNA_comname.eps", plot = speciesbubbleplot_eDNA_comname, units = c("in"), width = 7, height = 12, dpi = 300, )

NOTE on above. The common name plot has two entries in the Bay anchovy row because, as mentioned above, there are two different species name that are labelled as Bay Anchovy. Is it OK to group these as same species (Anchoa mitchilli)

NEXT next Sara wants the average rel abundances for each species across all dates

Import and prepare the data from trawls

Import Trawl Master sheet

# import 4th sheet from  Excel file which contains morphometric data for each individual collected for every date
trawl_master <- read_excel("Trawls MASTER 2020 _mod_ES.xlsx",4)
trawl_master

# and import 6th sheet which is station info
stations <- read_excel("Trawls MASTER 2020 _mod_ES.xlsx",6)
stations

NA

Convert to count table

Make an equivalent to an OTU table, grouping by date and location and representing counts for every unique species

trawl_counts <- trawl_master %>%
  group_by(DATECODE, STATION_NO, CommonName) %>%
  tally(name = "count")

trawl_counts

and link station names instead of numbers to count table

trawl_counts <- left_join(trawl_counts, stations, by = "STATION_NO")
trawl_counts

Abundance plots- Trawls

speciesbubbleplot_trawl_comname <- ggplot(trawl_counts, aes(x = STATION_NA, y = fct_rev(CommonName), color = STATION_NA)) + 
  geom_point(aes(size = log10(count), fill = STATION_NA), color = "black", pch = 21)+
  scale_size(range = c(1,15)) +
  scale_size_area(breaks = c(.01,.1, .3, .5, 1, 3), max_size = 6)+
  xlab("")+
  ylab("")+
  labs(size="Log(counts)", fill = "Station")+
  theme_bw() +
  scale_fill_brewer(palette="Paired") +
  theme(axis.title.x=element_blank(),
        axis.text.x=element_blank(),
        axis.ticks.x=element_blank()) +
  facet_grid(DATECODE~BAYSIDE, scales = "free", space = "free", drop= TRUE)

Scale for 'size' is already present. Adding another scale for 'size', which will replace the existing
scale.

speciesbubbleplot_trawl_comname

Export figure

ggsave(filename = "Figures/speciesbubbleplot_trawl_comname.eps", plot = speciesbubbleplot_trawl_comname, units = c("in"), width = 6.75, height = 15, dpi = 300)

CONTINUE HERE

Ordinations

PCA

PCA is essentially a type of PCoA using the Euclidean distance matrix as input. When combined with a log-ratio transformation of the count table, this is deemed appropriate for compositional datasets. It is also recommended as a first step in exploratory analyses.

First do a CLR, centered log ratio transformation of the absolute abundance data (after filtering), as suggested by Gloor et al. 2017

# Estimate covariance matrix for CLR-transformed ASV table
clr_asv_table_ps <- data.frame(compositions::clr(otu_table(ps)))

Generate the PCA and visualize axes

# Generate a Principle Component Analysis (PCA) and evaluated based on the eigen decomposition from sample covariance matrix. 
lograt_pca <- prcomp(clr_asv_table_ps) 
# NOTE- this is equivalent to first making a Euclidean distance matrix using the CLR data table and then running a PCoA. A Euclidean distance matrix of a log-transformed data table = an Aitchison distance matrix. So this is equivalent to the compositional methods listed in Gloor et al.

# Visual representation with a screeplot
lograt_variances <- as.data.frame(lograt_pca$sdev^2/sum(lograt_pca$sdev^2)) %>% #Extract axes
  # Format to plot
  select(PercVar = 'lograt_pca$sdev^2/sum(lograt_pca$sdev^2)') %>% 
  rownames_to_column(var = "PCaxis") %>% 
  data.frame
head(lograt_variances)

# Plot screeplot
ggplot(lograt_variances, aes(x = as.numeric(PCaxis), y = PercVar)) + 
  geom_bar(stat = "identity", fill = "grey", color = "black") +
  theme_minimal() +
  theme(axis.title = element_text(color = "black", face = "bold", size = 10),
        axis.text.y = element_text(color = "black", face = "bold"),
        axis.text.x = element_blank()) +
  labs(x = "PC axis", y = "% Variance", title = "Log-Ratio PCA Screeplot, CLR Tranformation")

A faithful representation is to plot this ordination in 2D because the 3rd and 4th axes explain very low % of variances, while the 1st and 2nd explain a decently large proportion of variance (15.7 + 10.5 = 26.2%)

Visualize the PCA-

lograt_pca$x #View PC values

             PC1        PC2         PC3          PC4          PC5         PC6          PC7          PC8         PC9        PC10
T1S10 -2.6238954 -0.3252536  1.27005712 -1.666211452  0.798649968 -0.57848189  0.247580998 -0.558711581  1.54051341 -1.00257763
T1S11  0.2705609 -4.0749320 -6.66931720  2.284305153  2.672326913 -0.41018048 -0.526654868 -0.462324083 -0.41629925 -1.22992687
T1S1  -2.7027302  2.5315244  0.42770674 -2.891886434 -0.089199476 -2.02741275 -1.526307265  4.507918543 -2.80161601  0.99281647
T1S3  -2.1044928  1.0756380  1.49045892 -2.219957763 -0.061377153 -0.38494915  0.320469272 -1.012257490  1.42749170 -0.65295542
T1S5  -1.7135917  1.1790076  2.77474051 -1.340062932 -1.364232051  0.24102503 -0.009868407 -0.958600452  1.66240096  1.90249139
T1S6  -1.6263823 -0.7382611  4.92533402 -2.100496346 -0.992855481  1.31005659  2.080679436 -0.291113329 -0.53023688 -0.48181295
T1S9  -1.8890736 -7.1882980  0.74791280  0.478128606 -1.223416026 -1.18521711  2.834417355  1.011107634 -1.91733560 -1.95236999
T2S10 -5.4723849 -3.7102032 -2.02733221  0.358739428  0.095792276 -4.19640555  1.696323226  0.708131115  1.11063176 -1.77725044
T2S11  4.0600493 -1.6653347  0.95792661 -1.382521282 -1.935788288  0.14614516 -0.219686405  0.066454230  0.28910892 -0.35381697
T2S1  -0.5256139 -1.6043596 -2.82111238  0.471370176  5.396921155  4.13619608  0.992107496 -1.578763421  1.80377493  2.18025904
T2S2  -1.5675813  3.4039386 -2.83994788 -1.328904319  1.293026359  3.90586508  4.611348013 -0.711643119 -2.75478280  1.19354776
T2S3  -2.4949331  1.8527466  0.55242812 -2.302859249  0.001024354 -1.64228999 -0.599524728 -0.235068104  0.87739077 -0.06120956
T2S4  -5.4192303 -0.5712951 -2.80407160  0.328311261 -0.473384127  3.55256896 -0.864999520  3.421745399 -2.94070397 -1.64572626
T2S5  -2.2024924  2.1002160  2.34821607  2.710381042  3.191568957 -0.90891012 -3.088217336  3.454337657  0.47494384  2.76967314
T2S6  -1.8637965 -5.0301644  2.83044061  0.651949689  2.536239781  2.28530167 -1.412309984  2.720676493  2.49919366  1.43936846
T2S9  -8.1183606 -4.0795361 -5.89618438  3.088417424 -6.620641957  0.18089576  0.254590155 -0.882108849  1.90441468  4.35599519
T3S10  4.6214005 -1.6575522  0.58946754 -1.320385118 -1.661933332  0.18164541 -0.035201214  0.001341068  0.26754996 -0.43305903
T3S1  -2.3913351  2.2896417 -0.20957141 -1.068738089 -0.640139573  0.63357839 -1.285553135 -1.195502284 -0.53495156 -0.32737072
T3S2  -2.2678012  3.3894600  0.27244730  2.244919808  0.035628741  0.18047505 -3.537238882 -0.264238101 -0.35901011  0.87134641
T3S3  -0.6141891  1.8274067 -1.15847880 -1.437042040  0.895015921  0.69099724  2.030728395 -1.239263664 -0.42837700  0.42179666
T3S4  -3.4730868  0.5900791  0.55663668 -1.944078098  1.248042434 -0.03954649  0.588369559 -0.373556187  3.33127230 -1.17587526
             PC11        PC12        PC13        PC14        PC15         PC16        PC17        PC18        PC19         PC20
T1S10  0.22597717 -0.49591596  0.62088813 -0.11135149 -0.90317596  0.052175005  0.51636597  0.11646915 -1.13617561 -0.939740199
T1S11 -0.33875912 -2.47937788 -1.92292360 -1.61727672  1.42629776  2.633399673 -1.77511843 -0.64393857 -0.16379258 -1.170843742
T1S1   0.42101859  0.65442210  0.05542544  1.05706121  1.01377542  1.748809810  0.60333600 -2.11186111 -3.09626558  1.781651311
T1S3   0.21932314 -0.65001251  0.19899498 -0.42992913 -0.17187489 -0.321107836 -0.29559955 -0.62907644 -0.98165385 -0.420964761
T1S5   0.90236276  2.37041721 -0.90409728 -5.95846889 -0.99039907  2.323748019  1.87406642 -0.52235594  0.47615803 -0.538955197
T1S6   0.32492687 -0.58250914 -3.36962676  1.03850812  2.92510401  0.527322477  0.74283517  1.98271154 -0.90769777  0.208257905
T1S9  -1.82706149  4.63700830 -1.41096275  1.65684273 -0.73128430 -0.439014716  0.22456025 -2.83124825  1.54026880 -1.804244119
T2S10 -0.63570055 -0.04821840  0.03027849 -2.11585154  1.52888813 -1.711272217 -2.05352206 -0.32604955 -0.43090515  1.805775529
T2S11  0.10750821 -0.16232384  0.22061834  0.06591853 -0.35834169 -0.180707353 -0.42978954  0.20962610 -0.45129627 -0.074319773
T2S1  -0.84361171  2.61168296 -1.64637670  0.47643508 -1.53112443 -0.783075685  1.14544456  0.43919900 -1.03784578  1.943550414
T2S2   1.90947454 -0.88042217  2.50315503 -0.71782729  2.65945940 -0.679764282  0.20848879 -1.61984898  0.76279443 -1.652676887
T2S3  -0.28832020 -0.58979394  0.08413418 -0.03476737  0.53372457 -0.528477113 -0.10571160 -0.13196257 -0.50579456 -0.513744834
T2S4  -1.73341212 -0.05444488  2.67180984 -1.40242616 -0.29205849  0.287767338  0.90589382  2.03117571 -0.08582432  0.517562229
T2S5   2.20888695  1.28719261  0.16320560  0.97886685 -0.43996377 -0.185431085  0.30838611 -0.78176830  0.76544762 -0.767696679
T2S6  -2.05629428 -1.67779276  0.06090643 -0.37825238  1.14814511  0.229027684 -1.04539827 -0.09822133  0.79124945 -0.201171927
T2S9   2.52542213 -1.21424602 -0.33127400  1.97232751 -0.63646116  0.587380408  0.56256483  0.20782020  0.12040843  0.385932778
T3S10  0.17608809 -0.09239084  0.27696903  0.01189034 -0.04774737 -0.240905695 -0.07265447  0.14762881 -0.33514522  0.142036307
T3S1  -1.77915713 -1.57684401 -2.40731062 -0.16246954 -1.13827510 -1.572223128  0.39958868 -0.62003482 -1.23180650 -0.908141905
T3S2  -1.80093781  1.40677342 -2.00653035  1.31217445  2.49078997 -0.331605766 -0.44636779  1.88665314  0.62390115 -1.979127915
T3S3  -0.19515396  0.64121705 -1.42175886  0.94633601  1.18314322  0.356666826  0.35724747 -0.39248176 -1.01111108  0.887210503
T3S4  -0.03337711 -1.22064722  1.41331871  0.55048179 -0.99424565 -0.090116768 -0.12121385 -1.12841112  0.14705172 -0.272828981
             PC21         PC22         PC23        PC24          PC25         PC26        PC27          PC28         PC29
T1S10  0.14553176  0.444887701  0.030555073 -0.10425935 -0.4649432055  0.355881811  0.17992733  0.7760907427 -0.627690690
T1S11  1.38300176  0.979099117  0.211703218  0.15116950 -0.8685434581  1.049405232 -1.10236127  0.0002552213 -0.767570144
T1S1   0.34009906 -0.271639014 -0.903345414  1.30069377 -0.5473422995 -0.048022311 -0.10948686 -0.9587529174 -0.015703705
T1S3   0.86994683  0.246913911 -0.158519509  0.12505746 -1.1016182738  0.059396108  0.01323105  1.2624136272  0.275632635
T1S5  -0.28004625 -0.600135978 -0.225638160 -0.22408151 -0.0009001045 -0.794429743 -0.71040916 -0.7007108564 -0.013510170
T1S6   0.30251073  1.892988844  1.479249040 -2.05668429  0.6892908892 -0.364245835 -0.08183022 -0.8163892316  0.653306565
T1S9   0.60401701 -0.026577052 -0.266982730 -0.05322975  0.3969389259  0.099425676 -0.35147954  0.1775020985  0.456170749
T2S10 -2.33247107 -1.423626311  0.484900870 -1.55699001 -0.7921676214 -0.407380274  0.94742076  0.0174250216 -0.392227697
T2S11 -0.37304090 -0.044363953 -0.212358865  0.03656853 -0.2055835293  0.405011932 -0.12423554 -0.1260813064  0.255872703
T2S1   0.51211253 -0.869077708  0.215385184 -0.23843593 -1.4081013750  1.359543178  0.89307294 -0.3493111760  0.367630027
T2S2  -1.23341832  0.332054911 -0.742253664  0.06444234  0.3595826030  0.578803687  1.26134666 -0.7590524011 -0.330851226
T2S3   1.15014708  0.327327365 -0.825669816 -0.49833503 -0.5864129208  0.557311711  0.31739992  1.1282591094  0.969019040
T2S4   0.65239653 -0.397745489 -0.437515949 -1.40322970  0.5273097762  0.006654982 -1.03730521  1.4003376711  0.686279185
T2S5  -1.53158603  1.099204218  0.981168725 -1.53870366  0.6821822418  0.606535859 -0.09598065  1.0952280391 -0.572618674
T2S6   1.14916912 -0.442956604 -0.031343541  1.53126698  1.1626853043 -2.294630143  1.30790014 -0.4321071978  0.039003479
T2S9  -0.06879790  0.314833969 -0.487910272  0.13571852 -0.0935417744 -0.111592202  0.13245163  0.0115432579  0.137289451
T3S10 -0.31137995  0.003053146 -0.131364000  0.14127153 -0.1147585816  0.378698308 -0.11600723  0.0008098405 -0.054375007
T3S1  -0.18259033 -0.941533760 -0.608857056 -0.32371094  1.3136321089 -0.314823572  1.28871003  0.3636956219  0.116792357
T3S2  -1.90095709 -1.656661333 -0.169026823  1.05756571 -0.7505352043  0.531616513 -1.01059260 -0.4445991478 -0.217363962
T3S3   0.23648113  0.150139986  0.744726257  1.08530156  0.9973389162 -0.297207577 -0.70397225  1.0798450685 -0.540203211
T3S4  -1.40747880  0.950362687  2.174998385  1.84091769  0.5522902416  0.509635655 -0.78582948  0.1257947674  1.529647938
             PC30        PC31         PC32         PC33         PC34          PC35         PC36         PC37         PC38
T1S10 -0.61090108 -0.29334392 -0.435556282  0.436122013  0.620570063  0.0752049091  0.364291442  0.222722389  0.853366974
T1S11  0.38683053 -0.47170713 -0.507376193 -0.200978899 -0.466127983 -0.0887001046  0.407399148  0.137577782 -0.114942713
T1S1   0.39068097 -0.29859127  0.422021427  0.016638837  0.130295349 -0.3423059226  0.099331214  0.004371715 -0.053692539
T1S3  -0.89085871  0.30772799  0.035796223  0.384888434  1.245611088  0.8423535329 -0.056811384  0.677715223  0.876394557
T1S5  -0.10448823 -0.34639788 -0.108416705  0.280931290 -0.214231135  0.2227704635  0.234041079  0.027794099 -0.168256122
T1S6   0.17543435 -0.16388918  0.408543638 -0.023459302 -0.021177178 -0.1444244416  0.084570850  0.490213102 -0.165936538
T1S9  -0.06692976  0.30760983 -0.009473703  0.040284195 -0.050039551  0.0235304169  0.049103401  0.134936707 -0.032580927
T2S10  0.45881864 -0.27229696  0.378141816  0.079696113  0.025621644  0.2220459377 -0.229916233 -0.116912242  0.023235021
T2S11 -0.07367150  0.04060642  0.327821556 -0.335943407  0.177567813 -0.2684558422  0.561488607  0.476894504  0.234251029
T2S1   0.22719978  0.38827525  0.282206264 -0.438390883  0.036965892 -0.1441772303  0.141507739  0.073251632 -0.131871600
T2S2  -0.33864908  0.16809097  0.064604371  0.086877729  0.002553673  0.1239108829  0.412985888  0.139172474  0.005935413
T2S3  -2.26654726  0.23001824  0.880133582 -0.079399503 -1.611846710 -0.0529833199 -0.104266043 -0.665332121 -0.874030961
T2S4   0.77112458  0.73081680 -0.074041702  0.112370407  0.295223675  0.4241879490 -0.004228575  0.091313711 -0.312300967
T2S5  -0.17121290 -0.74735265 -0.331455620 -0.613891167 -0.362680848 -0.2437333112 -0.107411964  0.564034865  0.585280991
T2S6  -0.45836363  0.59828788  0.257913281 -0.377057458 -0.112145871  0.2661286081  0.001694725  0.444611086  0.313382173
T2S9   0.04952467  0.28054101 -0.020026648 -0.062809756  0.036918082  0.0670041757 -0.061020750 -0.038346173  0.043463127
T3S10 -0.04433020  0.11256207  0.276748498  0.012290749  0.105555296 -0.3108955253  0.225398056  0.383416618  0.104263911
T3S1   0.78849208 -0.09561134 -1.600916711  1.062468681 -0.458306008 -1.1614572080  0.283387190 -0.270171409  0.076478396
T3S2  -0.40605694  0.55137855  0.461720824  0.721368991  0.554321865  0.4202858684  0.512499024 -0.227527215 -0.125192170
T3S3   0.02013393 -0.20179302 -0.865030680  0.385797223 -0.040604332  1.1497492465 -1.231478661 -0.824389167  0.413980530
T3S4   0.97160611 -0.31764671  0.039652545  0.203106279  0.405656989 -0.0564320934  0.292736573  0.165312522 -1.225094311
             PC39         PC40          PC41          PC42         PC43         PC44          PC45          PC46          PC47
T1S10 -0.38601496 -0.522398117 -0.2601828761  1.7425428517 -0.150037940 -0.022197976 -2.831425e-03 -0.0100519518 -2.038300e-16
T1S11 -0.22022127 -0.233355749 -0.0045061584 -0.2088644668 -0.045195931  0.051624214  6.578873e-03  0.0074415753  2.957704e-16
T1S1  -0.21897172 -0.033400842  0.1854388730  0.1027272364  0.079799837 -0.025304143 -5.997196e-03  0.0027479728 -9.393528e-16
T1S3  -0.75497648  0.603862482  0.6040479086 -1.0356859876  0.297725332 -0.016166585 -1.318602e-02  0.0043860796 -1.147520e-15
T1S5   0.26017909  0.053160901 -0.0241782401 -0.0575928258  0.020748744 -0.009410090  9.226674e-05 -0.0042139111  2.766017e-15
T1S6  -0.25843482  0.293010354  0.0953476162  0.1450311162  0.083660353  0.004693246 -1.979926e-02  0.0067988303  3.126839e-15
T1S9  -0.19310548  0.050539539 -0.0263737418  0.0752063777  0.060796962  0.005479383 -4.041996e-03  0.0066798004  5.663872e-16
T2S10  0.30388992  0.100877709 -0.0191138984  0.0412173967  0.026576122 -0.032226350 -3.521885e-03 -0.0070238059 -3.287301e-16
T2S11  0.28580250 -0.321592098 -0.4781464260 -0.4109621304 -1.159042956 -1.198398284 -2.007390e-01  0.0455439782 -1.189153e-15
T2S1  -0.11248568 -0.073344813 -0.0955302997 -0.0376190978 -0.004465990  0.023019713  8.557707e-03  0.0032389114 -1.001803e-15
T2S2   0.01410303 -0.018399653 -0.0723573078 -0.0394075311  0.055382093 -0.053886132  2.126331e-02 -0.0041445615  1.569925e-16
T2S3   0.47491853 -0.324154290  0.1113297600  0.0257086927  0.021247549 -0.026144440 -1.289991e-03 -0.0004957201 -1.286297e-15
T2S4   0.02175802 -0.371533083 -0.0654592950 -0.0335770823 -0.032892383  0.006709334  4.995619e-03 -0.0041659031  3.790371e-16
T2S5   0.28095908 -0.242536910  0.0130502993 -0.3851088178 -0.060000171  0.091145738  9.202016e-03  0.0107147824  7.953707e-16
T2S6   0.17245826 -0.168809317 -0.0903469935  0.0539771988 -0.089777526  0.067356765  4.954736e-03  0.0027736662  2.391316e-15
T2S9  -0.04763513 -0.036926578  0.0312385396  0.0438364840  0.023883432  0.018597761  5.213981e-03  0.0019178143 -2.351418e-15
T3S10  0.34199375 -0.272932684 -0.2206710864 -0.2167177793 -0.243551170  0.556300282  2.557553e-01 -0.8175569629 -5.924081e-16
T3S1  -0.17851876 -0.315320817  0.4560668700 -0.3531386713 -0.169198752  0.016921196 -1.278480e-02 -0.0068107404 -9.254750e-16
T3S2   0.12952809 -0.070809741  0.1503751764  0.0970471976  0.009140306 -0.010012191 -6.877311e-03 -0.0104988319 -3.981190e-16
T3S3   1.09009743  0.242828505 -0.7044769588 -0.1231401097 -0.397445764 -0.026921698  2.386564e-02 -0.0229946682 -2.870967e-16
T3S4   0.33863712 -0.189836596  0.1949792205  0.0225704339  0.229417048 -0.063472056 -6.409916e-03  0.0074190104  1.847481e-16
 [ reached getOption("max.print") -- omitted 26 rows ]

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pca_lograt_frame <- data.frame(lograt_pca$x) %>% 
  rownames_to_column(var = "SampleID")

# Merge metadata into the pca data table
pca_lograt_frame <- left_join(pca_lograt_frame, metadata, by = "SampleID")
head(pca_lograt_frame)

# Plot PCA with Station
pca_lograt_station <- ggplot(pca_lograt_frame, aes(x = PC1, y = PC2, color = Station)) +
  geom_point(aes(shape = Bayside), size = 4) +
  ylab(paste0('PC2 ', round(lograt_variances[2,2]*100,2),'%')) + #Extract y axis value from variance
  xlab(paste0('PC1 ', round(lograt_variances[1,2]*100,2),'%')) + #Extract x axis value from variance
  scale_color_brewer(palette="Paired") +
  ggtitle('CLR-Euclidean PCA') +
  coord_fixed(ratio = 1) +
  theme_bw()

pca_lograt_station

ggsave("figures/pca_clr.eps",pca_lograt_station, width = 7, height = 5, units = c("in"))

The CLR-Euclidean PCA reveals there is some separation according to East vs West. The PCA only explains ~26% of the variance so keep going with different ordinations to see if we can get a better representation

PCoA

The more traditional approach to ordinations is to do a PCoA on a distance matrix such as Bray-Curtis, Jaccard, or Unifrac. While these are not considered compositional approaches, when combined with pre-treatment (transformations) they become more appropriate. One such transformation that I will use here is the Hellinger transformation.

The different distance matrices also tell you a few different things about the dataset so I will run through this to try to see if I can tease those out.

Before calculating any distance matrix, do a transformation of the filtered count table. Hellinger transformation is the square root of the relative abundance, so calculate it based on the ps_ra object:

ps_hellinger

phyloseq-class experiment-level object
otu_table()   OTU Table:         [ 368 taxa and 47 samples ]
sample_data() Sample Data:       [ 47 samples by 8 sample variables ]
tax_table()   Taxonomy Table:    [ 368 taxa by 7 taxonomic ranks ]

First, Jaccard, which builds the distance matrix based on presence/absence between samples. It does not take into account relative abundance of the taxa. Therefore this functions well for determining differences driven by rare taxa, which are weighed the same as abundant taxa.

jac_dmat<-vegdist(otu_table(ps_hellinger),method="jaccard") # Jaccard dist metric
pcoa_jac<-pcoa(jac_dmat) # perform PCoA

# Extract variances from pcoa, from jaccard calculated dist. metric
jac_variances <- data.frame(pcoa_jac$values$Relative_eig) %>% 
  select(PercVar = 'pcoa_jac.values.Relative_eig') %>% 
  rownames_to_column(var = "PCaxis") %>% 
  data.frame
head(jac_variances)

# Make a screeplot
ggplot(jac_variances, aes(x = as.numeric(PCaxis), y = PercVar)) + 
  geom_bar(stat = "identity", fill = "grey", color = "black") +
  theme_minimal() +
  theme(axis.title = element_text(color = "black", face = "bold", size = 10),
        axis.text.y = element_text(color = "black", face = "bold"),
        axis.text.x = element_blank()) +
  labs(x = "PC axis", y = "% Variance", title = "Jaccard PCoA Screeplot")

The first two axes (19.0 + 9.6 = 28.6) are OK. But I am going to experiment and plot the first 3 axes since the 2nd and 3rd explain a similar amount of variance, 19.6 and 8.4% respectively

Plot in 3D with Plotly

# Extract variances from the jaccard pcoa
pcoa_jac_df <- data.frame(pcoa_jac$vectors) %>% 
  rownames_to_column(var = "SampleID")

# Merge metadata into the pcoa data table
pcoa_jac_df <- left_join(pcoa_jac_df, metadata, by = "SampleID")
head(pcoa_jac_df)

# Select eigenvalues from dataframe, round to 4 places and multiply by 100 for plotting. These will be the axes for the 3-D plot
eigenvalues<-round(jac_variances[,2], digits = 4)*100

# Plotly - 3-D
pcoa_jaccard <- plot_ly(pcoa_jac_df, type='scatter3d', mode='markers',
        x=~Axis.2,y=~Axis.3,z=~Axis.1,colors=~brewer.pal(11,'Paired'),
        color=~Station, symbols = c('circle','diamond'), symbol=~Bayside)%>%
  layout(font=list(size=12),
         title='PCoA Jaccard Distance',
         scene=list(xaxis=list(title=paste0('Co 2 ',eigenvalues[2],'%'),
                               showticklabels=FALSE,zerolinecolor='black'),
                    yaxis=list(title=paste0('Co 3 ',eigenvalues[3],'%'),
                               showticklabels=FALSE,zerolinecolor='black'),
                    zaxis=list(title=paste0('Co 1 ',eigenvalues[1],'%'),
                               showticklabels=FALSE,zerolinecolor='black')))
pcoa_jaccard

withr::with_dir('Figures', htmlwidgets::saveWidget(as_widget(pcoa_jaccard), file="pcoa_jaccard.html"))

The Jaccard-PCoA shows separation along axis 2 in East vs West differences.

Next, try a Bray-Curtis distance matrix with PCoA, which builds the distance matrix based on presence/absence between samples and relative abundance differences. This ordination will represent well the differences in samples that are driven by taxa with high relative abundances.

bray_dmat<-vegdist(otu_table(ps_hellinger),method="bray") # Bray-Curtis dist metric
pcoa_bray<-pcoa(bray_dmat) # perform PCoA

# Extract variances from pcoa, from jaccard calculated dist. metric
bray_variances <- data.frame(pcoa_bray$values$Relative_eig) %>% 
  select(PercVar = 'pcoa_bray.values.Relative_eig') %>% 
  rownames_to_column(var = "PCaxis") %>% 
  data.frame
head(bray_variances)

# Make a screeplot
ggplot(bray_variances, aes(x = as.numeric(PCaxis), y = PercVar)) + 
  geom_bar(stat = "identity", fill = "grey", color = "black") +
  theme_minimal() +
  theme(axis.title = element_text(color = "black", face = "bold", size = 10),
        axis.text.y = element_text(color = "black", face = "bold"),
        axis.text.x = element_blank()) +
  labs(x = "PC axis", y = "% Variance", title = "Bray-Curtis PCoA Screeplot")

The first two axes (27.7 + 14.3 = 42%) are pretty good again but I am still going to experiment in the plot with the 3rd axis since it is similar to the second (12.2% variance)

Plot in 3D with Plotly

# Extract variances from the jaccard pcoa
pcoa_bray_df <- data.frame(pcoa_bray$vectors) %>% 
  rownames_to_column(var = "SampleID")

# Merge metadata into the pcoa data table
pcoa_bray_df <- left_join(pcoa_bray_df, metadata, by = "SampleID")
head(pcoa_bray_df)

# Select eigenvalues from dataframe, round to 4 places and multiply by 100 for plotting. These will be the axes for the 3-D plot
eigenvalues<-round(bray_variances[,2], digits = 4)*100

# Plotly - 3-D
pcoa_bray <- plot_ly(pcoa_bray_df, type='scatter3d', mode='markers',
        x=~Axis.2,y=~Axis.3,z=~Axis.1,colors=~brewer.pal(11,'Paired'),
        color=~Station, symbols = c('circle','diamond'), symbol=~Bayside)%>%  
  layout(font=list(size=12),
         title='PCoA Bray-Curtis Distance',
         scene=list(xaxis=list(title=paste0('Co 2 ',eigenvalues[2],'%'),
                               showticklabels=FALSE,zerolinecolor='black'),
                    yaxis=list(title=paste0('Co 3 ',eigenvalues[3],'%'),
                               showticklabels=FALSE,zerolinecolor='black'),
                    zaxis=list(title=paste0('Co 1 ',eigenvalues[1],'%'),
                               showticklabels=FALSE,zerolinecolor='black')))
pcoa_bray

withr::with_dir('Figures', htmlwidgets::saveWidget(as_widget(pcoa_bray), file="pcoa_bray.html"))

These results are similar to Jaccard: the second axis seems driven by differences in East vs West. But there are clearly other things going on here with axies 1 and 3. I think this is a good representation of the data: together the 3 axes explain 54.13% of the variance.

NMDS

Lastly, try a non-metric dimensional scaling ordination. PCA/PCoA are metric and attempt to rotate axes to fit the distance matrix distribution. An NMDS represents the data in 2-axes, by constraining the distribution of the points. Similar to above, this can be combined with different pre-treatment of the data.

First try the compositional approach, an NMDS on CLR-tranformed data using the Euclidean distances (aka Aitchison distance)

euc_dmat<-dist(clr_asv_table_ps, method = "euclidean") # Build the Aitchison distance matrix
euc_nmds <- metaMDS(euc_dmat, k=2, autotransform=FALSE) # Run the ordination

Run 0 stress 0.2105436 
Run 1 stress 0.2128996 
Run 2 stress 0.2122615 
Run 3 stress 0.2111085 
Run 4 stress 0.2130327 
Run 5 stress 0.223828 
Run 6 stress 0.2127398 
Run 7 stress 0.2171268 
Run 8 stress 0.2233421 
Run 9 stress 0.2390473 
Run 10 stress 0.2232293 
Run 11 stress 0.2146083 
Run 12 stress 0.2343976 
Run 13 stress 0.2122711 
Run 14 stress 0.2175982 
Run 15 stress 0.2273345 
Run 16 stress 0.227759 
Run 17 stress 0.2231565 
Run 18 stress 0.2286921 
Run 19 stress 0.2426823 
Run 20 stress 0.2110142 
... Procrustes: rmse 0.01362479  max resid 0.06588342 
*** No convergence -- monoMDS stopping criteria:
     1: no. of iterations >= maxit
    19: stress ratio > sratmax

euc_nmds$stress #Check the stress. Less than 0.1 is good. Less than 0.05 is better. This will be different each time, since it is iteratively finding a unique solution each time (although the should look similar)

[1] 0.2105436

# Extract points from nmds and merge into data frame with metadata 
euc_nmds_df <- data.frame(euc_nmds$points) %>% 
  rownames_to_column(var = "SampleID")

# Merge metadata into the pcoa data table
euc_nmds_df <- left_join(euc_nmds_df, metadata, by = "SampleID")
head(euc_nmds_df)

## Plotting euclidean distance NMDS
nmds_aitch <- ggplot(euc_nmds_df,aes(x = MDS1, y = MDS2, color = Station, shape = Bayside)) +
  geom_point(size = 4) +
  scale_color_brewer(palette="Paired") +
  theme_bw() +
  labs(x = "NMDS 1", y = "NMDS 2", title = paste0('Aitchison Distance NMDS, Stress = ', round(euc_nmds$stress,2))) +
  coord_fixed(ratio = 1)

nmds_aitch

ggsave("figures/nmds_aitch.eps",nmds_aitch, width = 7, height = 5, units = c("in"))

The above has a relatively high stress (>0.2) so should be interpreted with caution. But it does show some separation East vs West along NMDS 1.

Next try a Jaccard NMDS, which will represent differences in presence/absence among samples, emphasizing both abundant and rare taxa the same

jac_nmds <- metaMDS(jac_dmat, k=2, autotransform=FALSE) # Run the ordination. Distance matrix was already calculated above

Run 0 stress 0.1627003 
Run 1 stress 0.1660244 
Run 2 stress 0.1496856 
... New best solution
... Procrustes: rmse 0.09100415  max resid 0.3183697 
Run 3 stress 0.1495161 
... New best solution
... Procrustes: rmse 0.05088368  max resid 0.3258651 
Run 4 stress 0.1578622 
Run 5 stress 0.1664404 
Run 6 stress 0.1572462 
Run 7 stress 0.1573408 
Run 8 stress 0.1495163 
... Procrustes: rmse 0.0009228226  max resid 0.004331749 
... Similar to previous best
Run 9 stress 0.1496491 
... Procrustes: rmse 0.01267127  max resid 0.07692795 
Run 10 stress 0.1709846 
Run 11 stress 0.1508712 
Run 12 stress 0.1496642 
... Procrustes: rmse 0.01285554  max resid 0.07716671 
Run 13 stress 0.1498306 
... Procrustes: rmse 0.05243516  max resid 0.3271674 
Run 14 stress 0.1496489 
... Procrustes: rmse 0.01266723  max resid 0.07694581 
Run 15 stress 0.149831 
... Procrustes: rmse 0.05247949  max resid 0.3275625 
Run 16 stress 0.1573579 
Run 17 stress 0.1496498 
... Procrustes: rmse 0.01268426  max resid 0.07733981 
Run 18 stress 0.1635248 
Run 19 stress 0.1498309 
... Procrustes: rmse 0.05245881  max resid 0.3273925 
Run 20 stress 0.1496495 
... Procrustes: rmse 0.01267903  max resid 0.07724868 
*** Solution reached

jac_nmds$stress #Check the stress. Less than 0.1 is good. Less than 0.5 is better. This will be different each time, since it is iteratively finding a unique solution each time (although the should look similar)

[1] 0.1495161

# Extract points from nmds and merge into data frame with metadata 
jac_nmds_df <- data.frame(jac_nmds$points) %>% 
  rownames_to_column(var = "SampleID")

# Merge metadata into the pcoa data table
jac_nmds_df <- left_join(jac_nmds_df, metadata, by = "SampleID")
head(jac_nmds_df)

## Plotting euclidean distance NMDS
nmds_jaccard <- ggplot(jac_nmds_df,aes(x = MDS1, y = MDS2, color = Station, shape = Bayside)) +
  geom_point(size = 4) +
  scale_color_brewer(palette="Paired") +
  theme_bw() +
  labs(x = "NMDS 1", y = "NMDS 2", title = paste0('Jaccard Distance NMDS, Stress = ', round(jac_nmds$stress,2))) +
  coord_fixed(ratio = 1)

nmds_jaccard

ggsave("figures/nmds_jaccard.eps",nmds_jaccard, width = 7, height = 5, units = c("in"))

This is still a relatively high stress (>0.1) so should be interpreted with caution. Similar to Aitchison-distance nMDS but there is a little more separation of East vs West on NMDS 2 axis.

Next try a Bray-Curis NMDS, which will represent differences in presence/absence among samples and relative abundance, thus emphasizing impacts of highly abundant taxa.

bray_nmds <- metaMDS(bray_dmat, k=2, autotransform=FALSE) # Run the ordination. Distance matrix was already calculated above

Run 0 stress 0.1628608 
Run 1 stress 0.1498312 
... New best solution
... Procrustes: rmse 0.08567004  max resid 0.321179 
Run 2 stress 0.1511991 
Run 3 stress 0.1496848 
... New best solution
... Procrustes: rmse 0.01159486  max resid 0.06870893 
Run 4 stress 0.1496492 
... New best solution
... Procrustes: rmse 0.05214599  max resid 0.3270977 
Run 5 stress 0.1805538 
Run 6 stress 0.1495165 
... New best solution
... Procrustes: rmse 0.01281364  max resid 0.07805366 
Run 7 stress 0.1511997 
Run 8 stress 0.1496853 
... Procrustes: rmse 0.05087238  max resid 0.3273574 
Run 9 stress 0.166339 
Run 10 stress 0.1496489 
... Procrustes: rmse 0.01281149  max resid 0.07792418 
Run 11 stress 0.1508707 
Run 12 stress 0.1568975 
Run 13 stress 0.1496846 
... Procrustes: rmse 0.05087779  max resid 0.3278401 
Run 14 stress 0.1625699 
Run 15 stress 0.1496844 
... Procrustes: rmse 0.05084287  max resid 0.327484 
Run 16 stress 0.1937921 
Run 17 stress 0.1710636 
Run 18 stress 0.1508709 
Run 19 stress 0.1648571 
Run 20 stress 0.1627921 
*** No convergence -- monoMDS stopping criteria:
    20: stress ratio > sratmax

Warning messages:
1: In readChar(file, size, TRUE) : truncating string with embedded nuls
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bray_nmds$stress #Check the stress. Less than 0.1 is good. Less than 0.5 is better. This will be different each time, since it is iteratively finding a unique solution each time (although the should look similar)

[1] 0.1495165

# Extract points from nmds and merge into data frame with metadata 
bray_nmds_df <- data.frame(bray_nmds$points) %>% 
  rownames_to_column(var = "SampleID")

# Merge metadata into the pcoa data table
bray_nmds_df <- left_join(bray_nmds_df, metadata, by = "SampleID")
head(bray_nmds_df)

## Plotting euclidean distance NMDS
nmds_bray <- ggplot(bray_nmds_df,aes(x = MDS1, y = MDS2, color = Station, shape = Bayside)) +
  geom_point(size = 4) +
  scale_color_brewer(palette="Paired") +
  theme_bw() +
  labs(x = "NMDS 1", y = "NMDS 2", title = paste0('Bray-Curtis Distance NMDS, Stress = ', round(bray_nmds$stress,2))) +
  coord_fixed(ratio = 1)

nmds_bray

ggsave("figures/nmds_bray.eps",nmds_bray, width = 7, height = 5, units = c("in"))

Very similar to Jaccard results. High-ish stress (0.15)

–> CONTINUE HERE

Summary

XXX